SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a374da0e028efaf7d15e300ad7b54355ed208bf6562593260be3c62d04e0fbb2' 
  AND token = 'xI1FijiYjk/IrQL0OeOhO4SaBiOBtFEaXNW5NbU6Odg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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