SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffac10831143315b3c0a4b7ff7dc4278dbbf1a5326d6d3f6fba1ca81d6b11557' 
  AND token = 'CbaeCHR4nrqWAKQZmcvpVUisUuwIv2BrEuNwsAH7QPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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