SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfee6760f2093187c64a93253875931ccd1750365840fbfab91a7ee83f647dce' 
  AND token = 'asjZwfp16zOP54eDzPFvwtOR4qjnb6PWjGaMs50M+fo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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