SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a29a984a954a54016ff9c96f7b09cd671ad670551373cb5eb6102681ff3fa40' 
  AND token = 'sf2vARoVuFBC2KA+xBdYKUv5YytEv7XvCUUipmpXriI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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