SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8d9467bcb93d24acc6433c61bb5c8cead12f125d91ff01e49bf66b72dc4a3c7' 
  AND token = 'pW0ix3U5QJAKkR6pHVxOHcMlNR2O3SdOMT6xdjRKyJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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