SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f21c44845cb59804e699dd5abfc23596a73eb6919b53f66db73e5400b6f6924' 
  AND token = 'OW31iyTtJZqEUvEMHJFloSHkdhLmwTHd0VlzGhWF8P0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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