SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c293dc3cd919b2a32992b6513821380e780bd5d6afe671983793133d309725e' 
  AND token = '3VJpTSUb3zCgA1Ho1vSGgijg0ChnwnlzYDs7djEgJ9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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