SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efea2b2e1027987433294643438f1a5bf540fe163cf5ad8163710e9132d42583' 
  AND token = 'A5Zmvo2pD9ouDLqdOE3MKp7hlJWMTFIPbiLFCtA8GPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}