SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36440e5326c2ebb8ad7fd24b9ba7fe21aab6769b7dda537fa227890b88baa799' 
  AND token = '53WxXkAUv+EFZBURkjnf19k86V3ceBq7dVOhTFQ8ffE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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