SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08abfdefeb1260786bcf671d73e9e5692181a495b521e970ff228ad92ea09f09' 
  AND token = 'imZtX0CI2et54OktuWtjDlpN7N+zuKldUA3j2VyzF5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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