SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5199c898c0a63097daa87a304ef2bfe80467e81ecdfb0196f691546fbc4506df' 
  AND token = '7/agNrzx2vPF88jcO7DKizsKqhTT4sKcP0hQ1E9f9EI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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