SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4157dbaaba5c7616cd63d4c941c6e15eaa8979a74b32587c897adeb8a313f763' 
  AND token = 'cDRqQJHfksf459rMzA3FUY5Z36RyByZqwgXKYLPj4QA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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