SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '933756dcc949f9857b6ab79ca3f29f20718abb6f9aa7b38edd2bb623039fd601' 
  AND token = 'NHVpC20GP//x3ww6sSlxDjzK+LcOsnx/33K/ldSjnCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}