SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac3d94da2abe34efab58962df65121c8957eae0cae8be36dfabbd657919d0f72' 
  AND token = 'xOmNI35twEKnbVNeC70Sykk0Z+3VsxyUeEreuuNbyxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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