SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50b6e1ccdf96c84eabbd83333403b82f53a11411d095516a6555b1918f9ba997' 
  AND token = 'aUipWGvBV1Rx2oYkaIYjxY9g5DxcnEPetS/EpVtWAsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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