SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62b3cfd6666ed2dba06b4c232232070099fee3a9a86f69b8e580735f4b1cfd92' 
  AND token = 'D0zcYlwJYQr4TTzhfvqjyL7k/OBMVocmgD0IkA7uqkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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