SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77a550c1dda7528b5627ef6dd252dca654666ac94b9ec2a5e9effcbf134e8c67' 
  AND token = 'i9MAkRPn/Mr7hmkEM9WGa7LwqEbbiRGP4MWvVHt6scw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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