SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bbd34ec90d9e7a5814bc594969f60a16ccd2e6c289f572d8ab7c17cfb81ef30' 
  AND token = 'EOvBfpD+BWBtKMlYw+wQdX+vho2n2mF+slm//oGoyRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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