SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16931a613d7c6fbe6c88d1bb9340cc101fa02aacefe7574a5b32fa17bf449890' 
  AND token = 'znJnxFD/Geb0bkU/N6oKqebqnaaP5EWMVD3UEBLc0pQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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