SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14de74a322b88f829f8f9b811665e67977dcd126ba37787e933aed90ea419141' 
  AND token = 'gy7AenD/x2NTfOLLPrP5Y+DMZGKvvkkvvVMMNmpQ7U8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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