SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ce4bf37cab6e0dd890f757c2f5cd0a856abcfd070e171672e38f34a9c71a737' 
  AND token = 'AeYTiycUIg6pXfk1JZOeRRFhxPGYWBtL4xs2On485WA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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