SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74e316f4581a8d674dc47ff58d0c2b448e011f8650bc308ce7ea8b46a56765e9' 
  AND token = 'b7hPV6lpMVtCJ/IBKwq5xmIrYncdB1P0qxwBCnTkvp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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