SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55e5d5b6bcd0b10c35a70330f34be3998b15145196c9b41a1d011d59df042f35' 
  AND token = 'KXmi7kId76V5xgiLyGs97gDZED+Fr63QPaMZXGWLzDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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