SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '794da5c26c7f4aa317207867a85df74423440b2ee79eda06311721b27b17f34d' 
  AND token = 'qJ0eArTBNRZHFNiGc/kMV16hVU4t5Xg5DZ+hDoAwuCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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