SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3efa31dbbedd008d50e094780ff3bbe48a9002b711a9954a430de9e18013dd12' 
  AND token = 'HEgeCuiLpF/nkLx4Si9CBndYtEcmihGkOqA6xHf3g6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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