SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8881c29aa20d6ab0a4f1afb15bc7a48213f08ad2945ecc218f30cbcae6bd3138' 
  AND token = 'aCPeybDH2pOTQZZJ6QBUg7vC37FfPUrCHlurufXjWAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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