SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c0c28c8176a612c062921a419b2ae0cf64731133c53269b490ba4dd0f8b973b' 
  AND token = 'jrefAW0CWoqtcrX/gvyNeRb5znQ2CX1ZECBADgWchm0=' 
  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"
    }
  }
}