SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6f6182afe22319d2281a535698f497847b6864f1ad20bdf41a7df018d3e759c9' 
  AND token = 'mLhZd4TXtyuwAp23UC2YYsgdAbTQtRnarm2UHKqa/EI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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