SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '538e7b614ef5797db903e4a501e0716227cb438c6b3b0ff765aac2bba77a535a' 
  AND token = 'c8okgHGPHGTIpiHqg4ncFVJU2gUNRzF3mRWkFfBOkbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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