SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfeb3679d82488f54140937b5c0d777a581427fd24468da2548b8fbf5248aa65' 
  AND token = 'kUikI2ONSj+GPjaqR3KNkIzdJ7N01+Cir/686OvpVwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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