SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '468d518602ac718ed47feea8913860078c26c0597542f36fda28edf2a630e623' 
  AND token = 'DFBJ8Uqgr2ljPfLSEWl/fnFBm9uRQE9QoSZpsPjt0nQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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