SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ac9d87e73cf6b3a26641eff42eee66acfedb097be16674d699fe47724a0f223' 
  AND token = 'IcgLybYJi+urvmCplarBdV8iN2OipuSxmzGS0ZFzjqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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