SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe68199036db232fe6227533e7b6b9734b47138467471372406cc4cf91e5c49b' 
  AND token = 'G9MyvybVtJe5hzPQExynJcZ/xicKFALZCJuZwscymAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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