SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4073bcc288490e6cec348d256be6ec4c1dcfd37666f7b8431b504fee55ce1b26' 
  AND token = '8hM9dPQ1hIV0qO2ZtYic/iJ5pceQz07cSuNRf9zCC/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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