SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8565dc52a148c2eb0231333b4593098033a74ed47b7ce8ee3eec70ee4259779' 
  AND token = 'Op+Eg8cPHHHDpsZGXPigthc5xb+xJjszDFlf59jStgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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