SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '343752ae5e30bf252c157bc487be9d679e9c43534bff84560d7eb2bd1d9e7f27' 
  AND token = 'ibBQZtnv1xKBmd8FOKNDXVIgOMK1iL8GFl7ZDLzIf7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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