SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dfc77d0fe5b5b4f5818f7603ab78a315f56547651320e0ebb27fbee141cb139' 
  AND token = 'BvZ5NXBVKtJGTYgKJMaGqgzp3+MKtibzWlX0k/KuMx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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