SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68c49f4356d8a3d265f02f2ef6ad31fca1bf8b1ed05f248e51d133873e783b8f' 
  AND token = 'GY6NbK4c+/Vshhd7xmwY5SGQTyzbg7fSZjjj1GmWlZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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