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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cf5e366ce8275eb944d2714dceae3d2534e100631ef4419f62d6af17e0f1fd1' 
  AND token = '3ZFfiIKHrM5SPzQ+T7G+Qi5t7uXEwfUjcISOlpp1GrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}