SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55326a3fc81fc005ee17edef4864f413ddd3fb28c4c7d95f741369271953ea79' 
  AND token = 'E3bLPSFvw2oSi4u5fq/SU8okfAGgqrBnSC7zxdGKW+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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