SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '955ca7fec6b7a4237b9d8cd2d0be76d847942df0b2c77c5e5e59901509bb2c51' 
  AND token = '9rRpN9V/N6S1H19pgLmBM1pEi9KbXw8GpPzGdjO/AT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}