SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '807584019df4f0931d760fcd188b5b0978b60b88421b105e5386bcaac70e211d' 
  AND token = 'pHwWhrEDmp4jyTfE8Leuy3FTiyonHyvFmPBFDVFSpbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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