SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffe9289b38077b6373c41879a9269f504c0bf7f6d722fcdadf5ff5c47ff666a4' 
  AND token = 'tJWcNs5+CQeNK8uYY6dfASBTlvLiJtEqHqWW0unJfDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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