SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe0aa9f7d99b6d2064a003912ea172672f6e937d8f71d8fb4403dfdf8e1b8161' 
  AND token = 'tccIsNBlDMeuAzoGoJnJfKlaqk5mX+TCEzkEhK/oDYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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