SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4869913782c8e2f55c09f6f220d73c5f8e58a8194ff0036773d2f2041cdb125' 
  AND token = 'weOAA4NoXqWsqKdvL5bn4UDhGhVXUrnETQIFSTZ+OrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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