SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88b8d97618c546a729b696ce0d4e83c12d9108781194164b84b62696ba29c576' 
  AND token = 'rp+7uijMeyaNdNojofoqFBiB5Fwc6pO/LUaMDfc2VoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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