SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3e12131f3a4c988b3c3a93d5c9dc45871abd9ff5b5df1bafe6d847074509a35' 
  AND token = 'XAwnHpbfHBLb/VJ50lZwv/eWYx37SOatY+769a1GTmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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