SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4614c2c71a59dc7d228786ab801dd159a6973ab57c9abdc21ece2fea1de138c' 
  AND token = 'T9ebOiPtNEtb5ZGfPT/4Y93F9swbiJe+TPVh+5DQenk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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