SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c555dd03a5746c014ef6c04cdf108115d9e72a6174f283d0940d68aed686b7fc' 
  AND token = 'kCnGUOnnld82Q0Y52MaO3f3a0+JPIQXRzhoFold3wvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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