SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5934b285518b9e4d570f0e2e86a807fad061b70ba581a9e816ae2a2bc54cad6f' 
  AND token = 'Tt35pMgbsdY/xragw/Z5z+7M1JYwm/+jSw1KL+mBLtg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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