SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7344e2fbe122d94e5064a83845edd96817fd8707dab4090a5d067feedd00ef19' 
  AND token = 'OnymVVLxQ7RhweUyZMgduyZVko1iixajK8C4AC5sdPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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