SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '140ce236d6bc3c1415cd32d80701b36ecfff2183c9b357ce00eeff424efa28f5' 
  AND token = 'mX7XCTq0sWp3fezMoARC/239Cs3rDW29cTbqQdRdvsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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