SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '270ab6823fb534e4b064abbfcbebd494e17231e09df4b8be67301ce3e5526a54' 
  AND token = '5yqYAi6g79OsR0sUIsboVKbn0Whe+U6oij0Yh8J6o+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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