SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7685571b90609e1804962c5d5ba987e4f1333d794f8f9e7a647224fdb71f008c' 
  AND token = 'vq5dQTKbBlLKawBf7fLpnZ+c4k48MkIHVp+utAjx2Lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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