SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f457578e70ce3192a9ca747fcd65692214fb4328c95de1836a68afa8a3e9d9d' 
  AND token = 'PkyfCub5vQectaDsgoidzMxubFoaOzhUJbnXBWZcir4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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