SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cc69288b2e94d13ac98db22687cbda8a75085de412a53f00ec503606a81ed09' 
  AND token = 'bDqpjUYN9LXZcpgDo6fnuE/m1JP6mdQgJ1kQRZ2J2gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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