SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ececd6e38895722e42b47e07478bdd2a5404f11c0c74b3e26c4d40de34b865e' 
  AND token = '5TPGTap26IoT9YSloeQSjVHeXIvxhhxiI1HWdJWQDfs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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