SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a241c8e89310181e7fb54e06befa4374d44aa511cb634bd379165582294eed15' 
  AND token = 'Au6WZPMiw8VMt+b+NLpDjVlY+MJ4FiyL1YzwUKdNqPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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