SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9f84184a21dbd66ec20fb5b6a33329941d6d7842c80236c7d38ea27263404bf' 
  AND token = 'tOCtzQOua1qClfrwmIkPcgUISPU2WgxyEe6wU+EXwe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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